MAY 21, 2025

Hi!

In Cipher this week:

• Bill Spindle gets a tour of the world’s largest nuclear facility, located in Japan, and delves into what it takes to restart a nuclear reactor.
• Bill also looks at how sustainable aviation fuel production has spiked in the U.S. in recent months.

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Send your energy photos, story tips and more to news@ciphernews.com.

A view of the Kashiwazaki-Kariwa nuclear facility from the main beach in the town of Kashiwazaki, Japan. Photo by Bill Spindle.

At world’s biggest nuclear plant, how to restart a giant

BY: BILL SPINDLE

KASHIWAZAKI, Japan — At the world’s largest nuclear power facility, seven massive reactors are lined up along the blustery coast of the Japan Sea.

All the reactors are idle, but the sprawling site is a beehive of activity. To one side construction workers add to fortifications. Below, workers discharge firehoses into a massive water reservoir. Inside the reactor and buildings housing electricity generating turbines, engineers and technicians monitor and maintain equipment.

They’re ready to go when the call comes, according to Masaki Daito, the deputy superintendent of the nuclear power station.

Most of these reactors were shuttered after an earthquake and tsunami in 2011 caused a reactor core to melt down at a similar facility on the other side of the country operated by the same company, Tokyo Electric Power Co., commonly known by its acronym TEPCO.

But TEPCO has been working to restart the two largest, most recently constructed reactors at the Kashiwazaki-Kariwa nuclear facility, often called KK.

It is one of just a handful of shuttered nuclear plants around the world working to produce power again. Most are in Japan, which shut down its entire nuclear fleet after the 2011 accident at TEPCO’s Fukushima Daiichi reactor.

Nuclear power provides a large — but shrinking — portion of the world’s carbon-free electricity. Long plagued by cost and safety concerns, the energy source has been experiencing a surge of interest in recent years due to growing urgency around climate change and increasing power demands for data centers and more.

But building a new nuclear plant takes billions of dollars and many years. One way to potentially speed up that process is to restart existing nuclear plants that have been idled or even partially dismantled.

Restarting a shuttered nuclear facility is cheaper and faster than building a nuclear reactor from scratch, said Jacopo Buongiorno, a nuclear science and engineering professor at Massachusetts Institute of Technology. “I wish we had more just sitting there,” he said.

Restarting Japan’s reactors has come with intense focus on lessons learned from the Fukushima disaster in 2011.

New security features have now been added to ensure a similar disaster wouldn’t cause problems at KK once the reactors have been restarted.

Driving with TEPCO officials along the beach beneath the towering reactor buildings, I follow a sea wall that has been built up so the top is 15 meters above sea level, higher than the tsunami that hit the Fukushima plant.

Offshore, a new low-barrier dam (technically known as a weir) is visible, used to retain sea water to cool the reactors during a tsunami (the sea recedes from the coast as a tsunami gains force offshore).

Emergency vehicles, a fleet of fire trucks and a 28-person emergency team are positioned 24/7, year around, on high ground — 35 meters above sea level — to ensure they are prepared to respond.

Protections are in place against not only earthquakes and tsunamis, but also fires, tornados, lightning strikes, cyber attacks and hostile acts from terrorists or military strikes.

Read this article and share it on Cipher’s website.

Lunchtime Reads and Hot Takes

Republicans strike pipeline permitting provisions from budget bill — POLITICO Pro (subscription)
Amena’s take: With a seven-vote majority in the House, GOP leaders are trying to garner all the help they can get, including President Trump's assistance, to pass the reconciliation package. Senate passage won't be as easy though.

Equinor says Trump has allowed Empire Wind to resume construction — E&E News (subscription)
Cat’s take: Democrat New York Governor Kathy Hochul worked hard to get the Trump administration to lift the stop work order. It's encouraging to see the wind project go forward, but what a lot of drama.

Climeworks’ capture fails to cover its own emissions — Heimildin
Anca’s take: Icelandic newspaper Heimildin does a data-based deep dive into how the company has been doing. On Swiss radio, its managing director said Climeworks is looking to cut 10% of its staff.

Data Centers’ Hunger for Energy Could Raise All Electric Bills — The New York Times
Cat’s take: The utility or the rest of the utility customers would end up covering the cost of the equipment needed to meet that power demand. Cost allocation issues are going to be a hot topic in years to come.

Zeldin could target a single word to undo endangerment finding — E&E News (subscription)
Amena’s take: "If EPA succeeds in defining power sector emissions as not 'significant' to climate change, it could have a cascading effect." Whether EPA has discretion per a Supreme Court ruling is an open question.

Decarbonizing the last few percent — Substack
Bill’s take: Smallish amounts of flexible gas generation can go a long way in allowing maximum renewable use without destabilizing the electricity grid, analyst Michael Liebreich and his podcast guest explain.

Conservatives Imperil G.O.P. Megabill That Would Fulfill Trump’s Agenda — The New York Times
Amena’s take: Voting against the measure, Rep. Josh Breechen (R-OK) said he wanted the clean energy tax credits phased out earlier. Note, the EIA ranks Oklahoma behind Texas and Iowa for wind energy generation.

More of what we're reading:

• World solar generation set to eclipse nuclear for the first time — Reuters

• Surfer, first lady and former PM among Brazil’s COP30 envoys — Climate Home News
• The Electric: With a Manganese War, GM and Ford Take Aim at China’s Battery Grip — The Information
• Summer heat waves could be trouble for stressed grid — E&E News (subscription)
  
  

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A behind-the-scenes tour of the world’s biggest nuclear power plant

Illustration by Nadya Nickels. Photos by Bill Spindle.

BY: BILL SPINDLE

Seen from a distance down the beach, the Kashiwazaki-Kariwa nuclear plant — the largest nuclear power facility in the world — cuts a giant, sprawling presence along the coast.

The highly secured grounds housing its seven reactors cover 4.2 million square meters.

Kashiwazaki-Kariwa, often called KK, hasn’t generated electricity since 2012.

I recently got a glimpse inside efforts to restart the facility.

After an overview of the plant at a TEPCO office outside the perimeter, our group — which consisted of me, deputy superintendent Masaki Daito and several TEPCO public relations executives — drove along the closely monitored, double-barrier fence line and turned into the main gate.

After a careful search of the company van and a check of my equipment — I was allowed to bring in a camera and a tape recorder, but not my mobile phone — we drove to a high point at the center of the grounds.

From there we could see across the line-up of the seven reactors along the coast, out to the seawall and breakwater.

We proceeded from there down to reactor number seven, which was first turned on in 1997.

More security checks took place as we entered the reactor building, including metal detectors, ID card checks for the TEPCO employees and biometric identification to ensure each of us was the person on our ID cards.

From there we entered a maze of tight corridors around the reactor that housed electrical equipment and infrastructure to monitor and control the reactor core at the top of the building. The entrances and exits of the hallways were sealed with watertight doors to prevent flooding of those areas and potential disruption of the facility’s power supply. An electronic musical tune sounded each time we opened a door to pass through, signaling it was unsealed.

Finally, we entered the vicinity of the reactor itself. Here, in addition to security, the area is tightly controlled and carefully monitored to detect any ambient radiation.

I had already donned a TEPCO jacket — color green for guests — as well as gloves and socks. Here we took off our shoes on one side of a barrier and proceeded with a second pair of company provided shoes to wear inside the radiation control zone. A radiation detecting device is fastened to anyone entering this zone.

Daito explained a series of safety mechanisms to prevent the accumulation of hydrogen — an explosive gas — around the reactor. That protection system was designed with multiple backups so it would work even if electricity were cut off.

Mechanisms to stop the nuclear reaction itself in an emergency were similar.

Working our way out of the plant meant a reversal of all the security checks on the way in, to ensure each person who came in actually left, without any safety issues.

Read this article and share it on Cipher’s website.

Sustainable aviation fuel gets off the ground

Source: U.S. Energy Information Administration • The SAF (plus other biofuels) production category includes sustainable aviation fuel, renewable heating oil, renewable naphtha, renewable propane, renewable gasoline and other emerging biofuels. It excludes ethanol, biodiesel and renewable biodiesel. SAF production capacity is an estimate based on company announcements and trade press and only includes hydroprocessed esters and fatty acids (HEFA) SAF.

BY: BILL SPINDLE

Production of sustainable aviation fuel is beginning to take off in the United States — but cleaner fuels still comprise a tiny slice of the overall fuel used in airplanes, according to the U.S. Energy Information Administration.

Reducing greenhouse gas emissions in aviation, one of the fastest-growing sources of emissions in many parts of the world, is a major challenge. Cross-country and international flights are especially emissions-intensive. And so far, clean substitutes for fossil jet fuel have been very expensive and limited.

Still, governments are beginning to require and incentivize the use of small amounts of sustainable fuels — generally made from plants (biofuels) and used cooking oils or manufactured using renewable energy — alongside fossil fuels. Burning these sustainable fuels in jet engines still produces carbon emissions. But those emissions are balanced by the carbon removed from the atmosphere in the process of making the fuels, either from growing the plants or manufacturing the fuels.

In the U.S., the Environmental Protection Agency’s Renewable Fuel Standard has worked alongside tax incentives and state programs to encourage the construction of production capacity over the past few years. Several of those facilities began kicking into gear late last year and early this year. The two lines in the chart above show that SAF production is suddenly shooting up as new capacity finally comes online.

It is unclear whether some of the policies that have led to SAF’s growth so far will survive efforts by Republicans in Washington to roll back policies that support renewable energy and climate action.

U.S. SAF production capacity increased by 25,000 barrels per day at the end of 2024, from near zero, as facilities in California and Texas came online, according to EIA’s analysis of company announcements and trade press. Production capacity jumped to 30,000 barrels per day by February 2025.

Overall production of “other biofuels,” EIA’s category that includes SAF but excludes the more established biofuels ethanol, biodiesel and renewable biodiesel, is expected to double in 2025 compared to last year, then rise another 20% next year, driven in large part by growing SAF production, the EIA said.

Still, those volumes represent less than 2% of the 1.7 million barrels of jet fuel used in the U.S. each day. Because the aviation sector overall is continuing to grow, the share of sustainable fuels in the overall fuel mix will remain about the same next year even after the additional production growth.

AND FINALLY...
Power spot

Cipher reader and principal at Maido Media Phil Keys took this picture of the PG&E Electra hydroelectric power plant in Amador County, California while visiting his brother earlier this year. The park in the Sierra Foothills near the plant is a popular place for locals, Keys told Cipher.

Each week, we feature a photo that is somehow related to energy, the thing we all need but don’t notice until it’s expensive or gone. Email your ideas and photos to news@ciphernews.com.

Editor’s note: In addition to supporting Cipher, Breakthrough Energy also supports and partners with a range of entities working to tackle climate change, including nonprofits, corporations, startups and research firms. For more information on Cipher’s editorial policy, click here.